Multiple Inlet flow regulator

ABSTRACT

A multiple inlet flow regulator with a restricted low-level inlet and upper-level overflow inlet is used to modify a new or existing storm water catch basin to regulate the flow of storm water from the catch basin into the sewer system. During periods of heavy rains and high flows into the catch basin, this flow regulator will allow the catch basin to serve as a temporary storage tank for storm water. The construction of these flow regulators can be accomplished using a variety of off-the-shelf components or custom fabrication, to achieve the desired effect of restricting the discharge from each catch basin in a combined sewer or storm water system as much as practicable without resulting in overflows onto the roadways. Key components include: restricted low level inlet that can be adapted in size to meet specific low flow conditions, upper level inlet sized to allow for the maximum discharge from the catch basin to prevent overflows onto the roadway, connections to the existing catch basin structure and covers to prevent floatable debris from discharging from the catch basin into the sewer system.

REFERENCES

U.S. Patent Doccuments 5,080,137 January 1992 Adams . . . 137/810

This invention relates to a multiple inlet flow regulator used in stormwater catch basins to regulate the discharge of storm water from thecatch basins to reduce the impact to the drainage system that couldresult in overflows or other negative impacts to the drainage system.

The multiple inlet flow regulator works due to the basic principals offluid flow including head pressure and flow through an orifice. Nomechanical or moving parts are required for this device. Multiple inletflow regulators are attached in front of the discharge pipe of a new orexisting storm water catch basin and are responsive to the rate of flowinto and out of the catch basin due to storm water runoff. Flowregulation using this device is achieved in three different phases:

Stage 1) Low intensity rain events, where flow into the catch basin isrelatively low, all of the flow into the basin will be discharged out ofthe low level outlet. Due to the low intensity there is no need toregulate the storm water flow out of the catch basin into the sewercollection system.

Stage 2) During moderate rain events, where the runoff is increased to alevel requiring flow regulation, the hydraulic restriction of the lowlevel outlet will regulate the storm water discharge out of the catchbasin. This regulation of flow will help prevent the downstream sewersystem from receiving flows beyond the system capacity that could resultin an overflow. As the discharge flow is regulated, the basin willretain the excess storm water at an elevation above the low leveloutlet. As the volume of storm water retained increases, the dischargerate will increase due to the increasing head pressure.

Stage 3) During intense rain events, the runoff entering the catch basinwill exceed the capacity of the low level outlet and the depth of stormwater stored in the basin will increase to the level of the upper leveloutlet. When this occurs all of the additional flow beyond the volumestored between the low level outlet and the upper level outlet will bedischarged through the upper level outlet. This outlet is sized inconjunction with the low level outlet to achieve the same flow volume asthe catch basins discharge piping, i.e. the addition of the multipleinlet flow regulator will not increase the potential for a catch basinto overtop allowing storm water to spill onto the roadway.

The inlet structures of the multiple inlet flow regulator are shieldedto prevent floatable debris from entering the device and fromdischarging from the catch basin. These shields serve two functions: toprevent the device from clogging and to prevent debris from entering thecollection system.

The flow characteristics associated with the multiple inlet flowregulator can be calculated using standard hydraulic analysis formulasfamiliar to civil or hydraulic engineers, including the Chezy-ManningEquation:

$V = {{\frac{k}{n}\left\lbrack \frac{A}{P} \right\rbrack}^{2/3} \times S^{1/2}}$V = Velocity  in  ft/s k = 1.486  (constant)n = Manning^(′)s  roughness  coefficientn = 0.014  for  concrete  pipe n = 0.011  for  PVC  pipeA = Area P = Wetted  perimeter S = Slope

and a modification of Bernoulli's Equation:

V=C _(v)(2gh)^(1/2)

-   -   C_(v)=Orifice coefficient    -   g=gravitational constant (32.2 ft/s²)    -   h=Hydraulic head in feet

Velocity is converted into flow volumes using the Continuity Equation,Q=V*A.

-   -   Q=Flow in cubic feet per second (CFS)    -   V=Velocity in feet per second    -   A=Area in square feet

It is the principal object of this invention to provide a costeffective, simple solution reduce combined sewer overflows and othernegative impacts associated with the rapid discharge of storm water fromcatch basins. Multiple inlet flow regulators can be mass produced andinstalled in a variety of existing application by semi-skilled workerswithout the need for specialized tools or training.

Another object of this invention is to provide a device that can beadapted to various system constraints including: desired low leveloutlet discharge, different catch basin structures (circular orrectangular), variations in catch basin depth and outlet pipingconfiguration.

Another object of this invention is to allow the catch basin to drainafter the storm subsides so there are no issues associated with a basin“holding” excess water above the catch basin sump (risk of drowning,insects, system is ready for the next storm).

For a better understanding of the invention, reference may be had to thefollowing detailed description taken in conjunction with theaccompanying drawings, in which:

FIG. 1 is a vertical sectional view of a storm water runoff catch basinwith a multiple inlet flow regulator according to one form of theinvention installed in front of the discharge pipe thereof.

FIG. 2 is a horizontal sectional view of a storm water runoff catchbasin with a multiple inlet flow regulator, taken on line 2-2 of FIG. 1according to one form of the invention installed in front of thedischarge pipe thereof.

FIG. 3 is a vertical view of the front of the invention, taken on line3-3 of FIG. 1 according to one form of the invention installed in frontof the discharge pipe thereof.

FIG. 4 is a vertical sectional view of one form of the invention takenalong line 4-4 of FIG. 2. Arrows indicating the flow path of the stormwater through the invention have been included in this view todemonstrate how the invention will work.

FIG. 5 is an enlarged and exploded side view of one form of theinvention showing the component parts.

FIG. 6 is an enlarged and exploded front view of one form of theinvention showing the component parts.

FIG. 7 is an enlarged horizontal sectional view of the vertical risersection (4).

FIG. 8 is an enlarged horizontal view, taken along line 8-8 of FIG. 5,depicting the low level inlet control section (1).

FIG. 9 is an enlarged view, taken along line 9-9 of FIG. 5, depictingthe low level inlet control section (1).

FIG. 10 is a vertical sectional view a storm water runoff catch basinwith an alternate form of the invention shown in front of the dischargepipe of the storm water catch basin.

FIG. 11 is a vertical section view of an alternate form of the inventiontaken along line 11-11 of FIG. 10.

FIG. 12 is a graph comparing to discharge rate over time from either asingle catch basin or a series of catch basins showing the reduction inpeak discharge rates achieved with this invention.

DETAILED DESCRIPTION

Referring to the first form of the invention shown in FIGS. 1 to 9,inclusive, 11 represents a catch basin for the collection of storm waterrunoff built from either pre-cast concrete or concrete block. This catchbasin 11 includes a base 14, vertical walls 13 where the walls caneither be rectangular in section or circular (drawings here are shownwith a rectangular configuration), a top section 28 that contains anopening 29 for storm water to enter the basin and a metal grate 12 thatfits into the opening 29. Such catch basins have an outlet or dischargepipe 14 that connects to a storm water collection system or a combinedsewer system.

Contained with in the catch basin 11, a multiple inlet flow regulatorcomprised of four pieces, 1 the low level inlet cap, 7 the unit basesection, 4 the riser section, and 5 the upper inlet cap.

The low level inlet cap 7, has five components to this individual piece:the 2 inlet screen, 3 inlet shield, 18 orifice opening, 19 cap gasket,and 30 cap section. The 2 inlet screen is a curved screen with openingsto allow storm water to enter into the device, but the curved screen isdesigned to keep floatables from entering into the device and to preventdebris from collecting on this screen that could lead to clogging of thedevice. The inlet screen 2, is connected to the 3 inlet shield and 30the cap section. The inlet shield 3 supports and provides rigidity tothe inlet and prevents floatables from entering into the device. The capsection 30 is similar in shape an function to a standard PVC pipe endcap. The cap section is a flat plate with flanges that contain the capgasket 19 to allow for a tight seal with the base unit 7. The cap gasket19 allows for a water tight connection with the base unit. The capgasket is fused to the cap section flanges. Within the flat plate of thecap section 30 is the orifice opening 18 that allows a restricted volumeof water to enter the invention through the low level inlet. The size ofthe orifice opening will vary upon the desired flow restriction based onspecific requirements for the application.

The base unit 7, has 3 component parts that connect to this unit: the 6base unit gasket, 8 mounting flange, and 31 the base unit inlet flange.The base unit is connected to the low level inlet cap 1 and the risersection 4. The connection to the riser section is made using a flaredopening in the top of the base unit that contains the base unit gasket 6that allows for a water tight connection. The base unit is connected tothe catch basin wall 13 using the mounting flange 8 that covers theperimeter of the base unit. The mounting flange can be bolted into thewall using expansion bolts 9, or connected using other methods such asepoxies or other adhesives. The base unit flange 31 is a circular flangethat allows for a connection with the low level inlet cap 1.

The riser section 4 is the simplest of the components of this form ofthe invention. This section is a generally rectangular in section withmounting flanges 8 for connection to the catch basin walls 13. Theconnection of the flanges would be accomplished as described for thebase unit 7, using expansion bolts or adhesives. The riser section isintended to be cut to length in the field during installation, allowingfor the necessary adjustments for catch basins of varying depths.

The upper inlet cap 5, is comprised of an inlet screen 10, mountingflange 8 and a lower frame 32. The lower frame 32 is connected to themounting flange 8 to allow for a frame to support the inlet screen 10 tobe at an angel. The inlet screen is designed to allow storm water toenter into the invention though this screen; this is the upper levelinlet. The inlet screen 10 is intended to prevent floatables fromentering the invention and to prevent clogging. The angle of the screenwill allow floatables to roll off and fall to the bottom of the catchbasin with the water level in the basin subsides.

Referring to the second form of the invention shown in FIGS. 10 to 11,inclusive, 11 represents a catch basin that connects to a storm watercollection system or a combined sewer system for the collection of stormwater runoff as previously described above. This form of the inventionis intended to demonstrate that a multiple inlet flow regulator can beconstructed using standard “off-the-shelf” piping commonly found in thestorm water and/or sewer industry. This form of the invention as shownin FIGS. 10 and 11 is representative of how standard piping can be used,but there are many other variations on the use of off-the-shelf piping.

The primary components of this form of the invention are all PVC pipingand include: 21 tee, 22 piping for riser section, 22 piping forconnection, 27 upper inlet screen, 19 end cap, 20 elbow (90-degree) forlow level inlet, 25 metal strapping for connection to catch basin walls,26 expansion bolt for connection to catch basin walls, 16 metal bandclamp for attach upper inlet screen and 22 rubber O-rings for connectionto existing outlet pipe. This configuration of the invention uses ashort section of piping 22 in conjunction with o-rings 22 to make aconnection into the catch basin discharge pipe 14. The short section ofpiping 22, and the other components would be one standard pipe sizesmaller than the discharge pipe 14 to allow the components to fittogether and to use the o-rings for the connection with the dischargepipe 14. The end cap 19 is a standard product that would need to bemodified as shown in FIG. 11. The modifications would include drillingan orifice hole 18, and attaching 20 an inlet shield consisting of a90-degree elbow. This inlet shield would prevent most floatable fromentering the invention. The inlet shield 20 can be connected to the endcap using an epoxy or other adhesive. The modification to the end cap 19would be the only modification to standard off-the-shelf componentsnecessary to make this form of the invention.

1. A multiple inlet flow regulator adapted for use in a storm watercatch basin having a low level inlet with an orifice sized to theindividual catch basins requirements in a given storm water or combinedsewer system with said orifice designed to regulate the discharge ofstorm water out of the catch basin as to extend the time required forthe storm water entering the basin to discharge from the basin into thestorm water or combined sewer system, thereby allowing the catch basinto act as a temporary retaining structure. The result of the flowregulation is a reduction in the peak discharge from both individualcatch basins and systems of catch basins as shown in FIG.
 12. 2. Amultiple inlet flow regulator adapted for use in a storm water catchbasin as described in claim 1 with an upper level inlet to limit thelevel of storm water retained in the basin to prevent the basin fromovertopping and flooding the surface above the catch basin structure. 3.A multiple inlet flow regulator adapted for use in a storm water catchbasin as described in claim 1 with a low level inlet screen to preventclogging and floatables in the catch basin structure from discharginginto the storm water or combined sewer system.
 4. A multiple inlet flowregulator adapted for use in a storm water catch basin as described inclaim 1 with a upper level inlet screen to prevent clogging andfloatables in the catch basin structure from discharging into the stormwater or combined sewer system.